Income Taxes (Income Tax Computed by Applying U.S. Federal Statutory Income Tax Rate) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income tax expense computed at the statutory rate	$ 102,803	$ 73,777	$ 104,888
Effect of tax-exempt interest	(50,740)	(51,624)	(49,166)
Tax benefit on dividends paid in our 401k plan	(1,764)	(1,851)	(1,743)
Bank owned life insurance income	(517)	(783)	(774)
Non-deductible FDIC premiums	2,629	1,790	1,267
Non-deductible compensation	1,773	1,123	1,708
Non-deductible meals and entertainment	625	786	1,299
Net tax benefit from stock-based compensation	(7,877)	(852)	(2,447)
Asset contribution to a charitable trust	0	(2,556)	0
Tax basis adjustment of premises and equipment	(1,026)	0	0
Other	553	360	838
Income tax expense, as reported	$ 46,459	$ 20,170	$ 55,870